zff - 2018-12-07

Hi,
i plan to install veracrypt hidden operation system. I will use 3 partitions. 1) windows 2) Hidden operation system 3) rest of the hard drive volume.
I would like to combine lateron the first and last partition and reinstall windows on it. So in the end I only have two partitions, but i am more flexible with the size of the partition of the hidden system.
(For example: 1 partition size 20 Gb(NTFS); 2 partition hidden operating system 100 Gb(NTFS); 3 partition 200Gb(NTFS). When i combine partition 1 and 3 and install windows again, then in the end I have one partition with the dummy system with 220Gb and the hidden system has 100Gb.)
Questions: Is this possible? Or is there any reason this will not work? Or will this procedure make it possible for somebody to detect there is a hidden system installed?
Best regards and thanks for your help